For a 32-year-old man with palpitations and tremulousness, what is the most likely underlying condition?

In the scenario described, where a 32-year-old man experiences palpitations and tremulousness, the most likely underlying condition is hyperthyroidism. This condition is characterized by an excess of thyroid hormones in the bloodstream, leading to increased metabolic activity and a range of symptoms including palpitations (rapid heart rate), tremors, weight loss, heat intolerance, and anxiety.

Hyperthyroidism is particularly common among this demographic and can be triggered by autoimmune conditions like Graves’ disease. The symptoms arise from increased sensitivity of the heart to catecholamines, as well as heightened metabolic demands, which can manifest as palpitations and tremors.

While panic disorder, pheochromocytoma, and Cushing's syndrome can also present with similar symptoms, they differ significantly in presentation and underlying mechanisms. Panic disorder is primarily characterized by episodes of intense fear or anxiety rather than sustained tremulousness or continuous palpitations typically seen in hyperthyroidism. Pheochromocytoma, although capable of causing palpitations due to catecholamine release, typically presents with paroxysmal symptoms including episodes of hypertension, headache, and sweating, and is rarer in this age group. Lastly, Cushing's syndrome tends to develop more chronic symptoms